INCREASING USE OF AGE-ADJUSTED D-DIMER

ABSTRACT

SESSION TITLE Quality Improvement SESSION TYPE Original Investigations PRESENTED ON 10/17/22 130 pm - 230 pm PURPOSE: Age adjusted D-dimer is a well validated method by which to rule out pulmonary embolism in patients with low to intermediate pretest probability. The specificity of the traditional D-dimer cutoff (500 mcg/L) decreases with age and leads to false-positive results and unnecessary imaging tests. When an age-adjusted cutoff is used (age x 10 mcg/L), specificity improves, and excessive testing is avoided. METHODS: We began by collecting retrospective data for all patients who underwent D-dimer testing over the course of a 29-month period (from October 2017 through February 2020) within our 400 bed community hospital. We determined how many of these patients underwent further imaging with either a CT angiogram (CTA) or ventilation-perfusion (VQ) scan. We then implemented a messaging system within the hospital’s electronic medical record (EMR) with the purpose of reminding providers to consider age-adjusted D-dimer values prior to ordering imaging. Post-intervention data was collected over a period of six months (August 2021 – January 2022). Patients who tested COVID positive were excluded from analysis. RESULTS: A total of 1054 patients were included in the pre-intervention group, while 371 patients were included in the post-intervention group. There was no significant difference in age between the two groups (p = 0.241). A total of 13.6% (n = 143) of the patients in the pre-intervention group underwent CTA or VQ scan despite having a D-dimer below the age-adjusted cutoff, indicating that the patient did not require any imaging. Post-intervention, a total of 9.2% (n = 34) of patients underwent CTA or VQ scan despite having D-dimer values below the age-adjusted cutoff. Using a chi-square test for association, there was a statistically significant decrease in unnecessary testing (χ2(1) = 5.343, p = 0.021). CONCLUSIONS: Despite high quality evidence that suggests the use of age-adjusted D-dimer is safe and effective for ruling out pulmonary embolism, many imaging tests are ordered based upon standard cutoff values. Implementing a reminder message within our hospital’s EMR system produced a significant reduction in inappropriate imaging. This ultimately resulted in less radiation for patients, as well as an estimated cost savings of $33,758 over a six-month period. Although statistically significant improvement was seen, further interventions, such as automatically adjusting D-dimer cutoff values within the EMR, may further reduce unnecessary imaging and avoid pop-up message fatigue. CLINICAL IMPLICATIONS Built-in EMR reminders to use age-adjusted D-dimer cutoff values may decrease unnecessary CTAs and VQ scans. This may translate into reduced patient irradiation and decreased overall healthcare costs without sacrificing patient care. DISCLOSURES No relevant relationships by Naren Bhupatiraju No relevant relationships by Meagan Mayo No relevant relationships by Katherine Reano